Yamaha dt250 1972
Posted 19 March 2012 - 04:32 PM
Posted 20 March 2012 - 12:04 AM
My only conclusion is that something big happened when it died. But I've never had such a problem so it's a little over my head. You're lucky to have a machine shop where you are though... Make sure the head gets hoaned correctly, you get a nice new piston (and other stuff), and make sure to dip a magnet down in the crankcase to see if any crud comes up, because the ring may have fallen down there.
Posted 20 March 2012 - 05:36 AM
Posted 20 March 2012 - 11:13 PM
Well good luck, be sure to keep us updated. If you have any questions that I don't know I can ask around.
Posted 23 March 2012 - 03:50 PM
Posted 23 March 2012 - 04:02 PM
Did you get around to measuring the actual bore before ordering? That's kinda why I hate the idea of plating the jug because it confuses everything... But yeah, measure everything up, see what you get, and go from there.
Posted 23 March 2012 - 08:13 PM
Posted 24 March 2012 - 03:37 PM
Posted 25 March 2012 - 01:00 PM
Correct me if I'm wrong but the piston that was in it did work at some point right? Does that piston have any indicators on it? Can you measure it? It's been a little while since I did a top end but you might be looking for a piston about the size of 69.8-9? Find out what size piston you need to fit into the cyl. Then look for a piston that was made for your bike in that size. I know Wiseco's website has all the available sizes. If none of them match your current jug, my uneducated suggestion would be to get it bored to a size that fits the common/std piston size for the bike.
Posted 25 March 2012 - 03:28 PM
I cant tell if its right so Im trying to talk to the company...the site you gave me doesnt list a dt2
Wow that's really weird they don't even list the size... Correct me if I'm wrong but you do know the std. jug size right? Sorry it's a lazy Sunday for me
Posted 25 March 2012 - 07:45 PM
Oh ok gotcha. Then yeah I'd wait to hear back from the seller of the piston to see if they have any info.
Posted 27 March 2012 - 07:31 PM
Before buying a piston kit, Take your cylinder to your local shop. Have them check it and tell you what oversize piston to get (one over,two over..), then order the piston kit and they will bore and hone to perfectly fit the cylinder to the piston. This usually runs about $60 or so.
This all could have happened from 3 reasons.
!. clogged carb made it run lean
2. timing/points off time
3. crank seals bad creating lean run
Most likely cause for an old bike like this= wore main bearings allowed crank seals to leak (my 75 DT 175 did this twice before i learned the hard way)
Edited by yellowsnow, 27 March 2012 - 07:34 PM.
Posted 29 March 2012 - 04:09 PM
Posted 29 March 2012 - 04:32 PM
Posted 29 March 2012 - 08:46 PM
Does that thing still have the original oil tank and oil pump system on it or are you premixing the fuel now? Make sure it's getting enough oil before you try running it again.
Posted 30 March 2012 - 09:03 AM
Most parts are readily available through sellers on ebay. The hardest parts to find are crank seals, one is still available, but the other is made of unobtainium and tough to find. there was a guy selling sets on ebay a few years back though. You can also try a local bearing/seal company and see if they can match up a seal thats the right size and application.
Good luck and have FUN on it!
Posted 31 March 2012 - 08:34 AM
Posted 31 March 2012 - 11:32 AM
Edited by yellowsnow, 31 March 2012 - 11:34 AM.